Yeah, there aren't so many muppet couples out there. Piggy & Kermit, Floyd & Janice, Gonzo & Camilla, Waldorf & Astoria and... that is all, I guess.
Now if we're talking all sorts of duos, including friendly/brotherly relationship and not just romantic couples, then there are so many great ones. I always loved the Gonzo & Rizzo pairing in the movies, for instance.